The idea that I am testing is a scenario in which the succession specified by the Treaty of Troyes becomes more or less stable. For a point of divergence, let's say Henry V lives long enough to see the defeat of the man who historically became Charles VII of France. If that is not plausible, let's just say that for whatever reason, the House of Valois is no longer a threat to the House of Lancaster's claim to the French throne. Once Henry V dies, Henry VI of England becomes either Henri II or Henri III of France depending on whether or not we go with a slightly longer lived Henry V. While Henry VI/Henri III manages to hold onto his French crown, he is eventually deposed in England. This results in a situation in which Henry and his heirs are Kings of France, but England is, at least for the time being, ruled by the House of York.